In a large bowl, whisk together half of the soy sauce, half of the sherry, half of the cornstarch, and salt. Add the chicken, toss to coat, cover, and let stand for 30 minutes.
Make the cornstarch mixture
Meanwhile, in a small to medium bowl, whisk together the remaining soy sauce/coconut aminos and sherry, plus the red wine vinegar, chicken broth, sugar and remaining cornstarch. Set aside.
Cook the kung pao chicken
Heat a wok or a large skillet with high sides over medium heat, then add 1 tablespoon of the oil. Add the peanuts and cook, stirring regularly, for about 2 to 3 minutes. Once the peanuts are golden brown, remove from the pan and set aside on a bowl or plate.
Add the remaining 2 tablespoons of oil to the wok. Add the chili peppers and stir-fry just until they begin to lightly char, about 1 minute.
Add the chicken and stir-fry for 2 to 3 minutes, lightly browning all sides. Add the ginger and stir-fry until the chicken is cooked through, about 1 minute more. Add the green onions and peanuts, then pour in the cornstarch mixture and stir until the sauce boils and thickens, about 1 to 2 more minutes.
Garnish with sesame seeds and red chili flakes, if desired. Serve immediately.
Notes
STORAGE: Store leftovers in an airtight container in the refrigerator for up to 4 or 5 days. CHICKEN: You can use boneless, skinless chicken breasts or thighs. Be sure to cut the chicken into equal size pieces so that they cook evenly. COCONUT AMINOS: Coconut aminos are naturally gluten-free and lower in sodium than soy sauce. You can substitute soy sauce if you don't need/want a gluten-free dish.CORNSTARCH: Pure cornstarch is naturally gluten free. You can substitute arrowroot powder, tapioca starch, or potato starch for cornstarch.